1. Field of the Invention
The present invention relates generally to electrical connectors. More particularly, the present invention relates to an RJ-type electrical receptacle having interference projections for preventing complete insertion of electrical plugs with misaligned contacts.
2. Description of the Prior Art
Modular jack plugs are well known in the art for use in terminating electrical cables containing multiple insulated conductor wires. The manufacturing process used to terminate those cables involves using a plurality of contact tines seated inside the jack plug that cut through the insulation on the conductor wires in the cable thereby making electrical contact with those conductors. Historically, that manufacturing processes posed quality control problems resulting in the misplacement of the plug contacts. For example, if, during manufacturing, the conductors in the cables were not completely connected to the plug contacts (or vice versa), or the contacts were not completely situated in the plug housing slots, the plug contacts would be misaligned relative to the plug housing or become misaligned with use.
A jack plug with one or more misaligned contacts can damage a corresponding receptacle as it is being mated with that receptacle. For example, if a misaligned contact on the plug is lower than it should be, the leading edge, or tip, of the misaligned contact will impact the corresponding mating receptacle contact and cause it to be deformed. Once deformed, the receptacle contact will thereafter be misaligned. Then, upon the insertion and mating of a different plug having properly aligned plug contacts, the mating of the plug and the receptacle may not provide the required electrical contact, thereby becoming unreliable and failing to meet specifications.
A general solution for preventing the insertion of a plug of one type of equipment in a receptacle of another type of equipment has been to implement industry standard sizes for various interconnect applications. The International Organization for Standardization (ISO) 31.220.10, for example, provides standardization for electromechanical components related to electronic and telecommunications equipment, specifically plug-and-socket devices. Thus, for example, an RJ-type receptacle for telephony applications is not designed to accommodate a BNC cable termination plug used in video and data transmission applications because the BNC plug and RJ receptacle have different shapes and sizes. Similarly, an RJ-11-type receptacle is not designed to accommodate an RJ-45-type termination plug because the RJ-45 plug is too large to fit inside the insertion passage of an RJ-11 receptacle.
Another solution for preventing the insertion of a plug into the wrong receptacle is to provide labels or the use of colored materials on the interconnecting parts. For example, a receptacle labeled with “RJ-45” and a plug labeled with “RJ-11” could inform the user of the incompatibility of the two devices. Or, the RJ-45 receptacle could be made out of a black plastic material that is a different color than the plug to inform the user of the incompatibility.
Another solution for preventing the insertion of a plug into the wrong receptacle is to use an interference stop. For example, since an RJ-11 plug is smaller than the opening of an RJ-45 plug and, thus, could be inserted into an RJ-45 plug, an interference stop that is integral to the RJ-45 receptacle can be used to prevent such an insertion.
Interference stops are disclosed in U.S. Pat. No. 6,375,516 to Trinh. In that patent, FIG. 5 illustrates interference stops protruding into the insertion passage of a receptacle from the bottom of the molded plastic housing. The stops, which are disclosed as being 0.024 inches in length, 0.20 inches wide and 0.017 inches high, are positioned to block full insertion of an RJ-11 plug into an RJ-45 receptacle. In U.S. Pat. No. 6,186,835 to Cheshire, a flexible barrier stop is provided that, as shown in FIG. 3, displaces out of the insertion cavity of the receptacle and allows an RJ-45 plug to be fully inserted but does not displace completely if a small RJ-11 plug is inserted. U.S. Pat. No. 6,257,935 to Zhang et al. discloses the use of two spring members positioned within an RJ-45 receptacle for preventing the insertion of an RJ-11 plug.
Thus, the solution to preventing insertion of the wrong size or wrong type of plug into a receptacle has been to use industry standard plug and connector sizes and configurations, prominent labels, different colored materials, and/or interference stops, among other methods. None of those solutions, however, are suitable solutions to the aforementioned problem of preventing mating of corresponding plugs and receptacles where the plugs have misaligned contacts.